<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
</head>

<body>
    <script>
        (function(window, document, undefined) {
            var hearts = [];
            window.requestAnimationFrame = (function() {
                return (
                    window.requestAnimationFrame ||
                    window.webkitRequestAnimationFrame ||
                    window.mozRequestAnimationFrame ||
                    window.oRequestAnimationFrame ||
                    window.msRequestAnimationFrame ||
                    function(callback) {
                        setTimeout(callback, 1000 / 60);
                    }
                );
            })();
            init();

            function init() {
                css(
                    ".heart{width: 10px;height: 10px;position: fixed;background: #f00;transform: rotate(45deg);-webkit-transform: rotate(45deg);-moz-transform: rotate(45deg);}.heart:after,.heart:before{content: '';width: inherit;height: inherit;background: inherit;border-radius: 50%;-webkit-border-radius: 50%;-moz-border-radius: 50%;position: absolute;}.heart:after{top: -5px;}.heart:before{left: -5px;}"
                );
                attachEvent();
                gameloop();
            }

            function gameloop() {
                for (var i = 0; i < hearts.length; i++) {
                    if (hearts[i].alpha <= 0) {
                        document.body.removeChild(hearts[i].el);
                        hearts.splice(i, 1);
                        continue;
                    }
                    hearts[i].y--;
                    hearts[i].scale += 0.004;
                    hearts[i].alpha -= 0.013;
                    hearts[i].el.style.cssText =
                        'left:' +
                        hearts[i].x +
                        'px;top:' +
                        hearts[i].y +
                        'px;opacity:' +
                        hearts[i].alpha +
                        ';transform:scale(' +
                        hearts[i].scale +
                        ',' +
                        hearts[i].scale +
                        ') rotate(45deg);background:' +
                        hearts[i].color;
                }
                requestAnimationFrame(gameloop);
            }

            function attachEvent() {
                var old = typeof window.onclick === 'function' && window.onclick;
                window.onclick = function(event) {
                    old && old();
                    createHeart(event);
                };
            }

            function createHeart(event) {
                var d = document.createElement('div');
                d.className = 'heart';
                hearts.push({
                    el: d,
                    x: event.clientX - 5,
                    y: event.clientY - 5,
                    scale: 1,
                    alpha: 1,
                    color: randomColor(),
                });
                document.body.appendChild(d);
            }

            function css(css) {
                var style = document.createElement('style');
                style.type = 'text/css';
                try {
                    style.appendChild(document.createTextNode(css));
                } catch (ex) {
                    style.styleSheet.cssText = css;
                }
                document.getElementsByTagName('head')[0].appendChild(style);
            }

            function randomColor() {
                return (
                    'rgb(' +
                    ~~(Math.random() * 255) +
                    ',' +
                    ~~(Math.random() * 255) +
                    ',' +
                    ~~(Math.random() * 255) +
                    ')'
                );
            }
        })(window, document);
    </script>
</body>

</html>